This invention relates to stimulation of bone growth in the femoral head, and particularly to devices and methods used to treat osteonecrosis of the femoral head.
Osteonecrosis, or avascular necrosis (AVN), of the femoral head is a serious medical condition which afflicts about 20,000 people per year. Due to poor blood circulation to the head of the femur, bone necrosis occurs. As the body tries to remove the necrotic bone by osteoclastic resorption, the head of the femur weakens and eventually collapses, leading to total hip replacement.
Core decompression is a common procedure used to treat and retard progression of osteonecrosis of the femoral head that involves cutting a channel from the lateral cortex, just beneath the flare of the trochanter, into the necrotic bone of the femoral head. Various trials have been conducted to determine the effectiveness of core decompression on the treatment of osteonecrosis of the femoral head, with some including the use of bone grafting and electrical stimulation to study their effects on treatment.
In core decompression procedures utilizing electrical stimulation in addition to bone grafting to treat osteonecrosis of the femoral head, direct current bone growth stimulators have been used in conjunction with normal cancellous bone material removed from the trochanteric region and distal neck to improve the effectiveness of the treatment. In these procedures, the cathode electrodes of the stimulators have been wrapped around bone chips removed from the core decompression channel and sutured into place for placement into the core decompression channel.
Cathode placement devices are known to be used with direct current electrical stimulators to provide control of placement of the direct current electrical stimulator cathode and to alleviate migration of the cathode. An example of a cathode placement device is the EBI OsteoStim® CorticalLok bone dowel. The OsteoStim CorticalLok bone dowel is designed for placement across bone fractures to stimulate bone fusion, having distal and proximal portions designed to hold the intermediate shaft portion in position across a bone fracture.
There remains a need for a cathode placement device for the treatment of osteonecrosis of the femoral head that is adapted for use in conjunction with core decompression surgical procedures.